BLOOMINGTON, Ind. -- Scientists and policymakers should draw on experience from the distant past to develop a new paradigm for protecting ecosystems at a time of accelerating global change, an Indiana University paleontologist and co-authors write in a paper published today.

The article in the journal Science calls for merging conservation biology with evidence from paleobiology -- the study of the fossil record of the history of life -- and the Earth sciences. P. David Polly, professor of geological sciences in the IU Bloomington College of Arts and Sciences, is one of the authors.

The authors say factors such as climate change, resource overconsumption and pollution are reaching a point where it is no longer realistic to focus only on protecting ecosystems from change. Instead, they argue, we need an approach that conserves the ability of ecosystems to adapt to changing conditions.

"It's a way of working with ecosystems that we know we’re going to lose," Polly said. "Instead of trying to maintain them in past optimal states, we would try to maintain productivity in the face of change."

Environmental change has sped up dramatically over the past 50 years, the authors write, overwhelming ecosystems that have existed for millennia. Atmospheric carbon dioxide has surpassed 400 ppm for the first time since more than 15 million years ago, which scientists say signals irreversible climate change. Human population is projected to grow by 3 billion by 2050.

Until recently, the dominant conservation paradigm has been to protect ecosystems from being altered. But scientists believe that is no longer possible, in many cases.

Going forward, maintaining vibrant ecosystems will require finding ways to manage for their "functional integrity" -- the ability to withstand or adapt to changes caused by human activity without losing their essential character -- rather than focusing on protecting particular species or unsullied habitats, the authors say.

Conservation decisions, they say, will increasingly need to balance trade-offs among maximizing biodiversity, preserving wilderness and maintaining ecosystem services such as food production, human enjoyment of nature, fresh air and clean water.

Making those decisions will require a better understanding of how ecosystems change over time, why certain species survive while others die off, how changes in climate affect plant and animal populations and when an ecosystem reaches a "tipping point." That's where paleobiology comes in.

Paleobiologists can contribute to that understanding, Polly said, because they study the record of what happened during environmental changes of the past -- as opposed to conservation biologists, who focus on change from a fixed, present-day baseline.

"This provides a different framework of thinking about ecosystem change," he said. "In paleontology, there's no such thing as a baseline. Instead, we have a record of change on many scales."